NMR STRUCTURE OF THE TUMOR SUPPRESSOR BIN1: ALTERNATIVE SPLICING IN MELANOMA AND INTERACTION WITH C-MYC
[BIN1_HUMAN] Defects in BIN1 are the cause of centronuclear myopathy type 2 (CNM2) [MIM:255200]. A congenital muscle disorder characterized by progressive muscular weakness and wasting involving mainly limb girdle, trunk, and neck muscles. It may also affect distal muscles. Weakness may be present during childhood or adolescence or may not become evident until the third decade of life. Ptosis is a frequent clinical feature. The most prominent histopathologic features include high frequency of centrally located nuclei in muscle fibers not secondary to regeneration, radial arrangement of sarcoplasmic strands around the central nuclei, and predominance and hypotrophy of type 1 fibers.
[BIN1_HUMAN] May be involved in regulation of synaptic vesicle endocytosis. May act as a tumor suppressor and inhibits malignant cell transformation.
Publication Abstract from PubMed
The N terminus of the c-Myc oncoprotein interacts with Bin1, a ubiquitously expressed nucleocytoplasmic protein with features of a tumor suppressor. The c-Myc/Bin1 interaction is dependent on the highly conserved Myc Box 1 (MB1) sequence of c-Myc. The c-Myc/Bin1 interaction has potential regulatory significance as c-Myc-mediated transformation and apoptosis can be modulated by the expression of Bin1. Multiple splicing of the Bin1 transcript results in ubiquitous, tissue-specific and tumor-specific populations of Bin1 proteins in vivo. We report on the structural features of the interaction between c-Myc and Bin1, and describe two mechanisms by which the binding of different Bin1 isoforms to c-Myc may be regulated in cells. Our findings identify a consensus class II SH3-binding motif in c-Myc and the C-terminal SH3 domain of Bin1 as the primary structure determinants of their interaction. We present biochemical and structural evidence that tumor-specific isoforms of Bin1 are precluded from interaction with c-Myc through an intramolecular polyproline-SH3 domain interaction that inhibits the Bin1 SH3 domain from binding to c-Myc. Furthermore, c-Myc/Bin1 interaction can be inhibited by phosphorylation of c-Myc at Ser62, a functionally important residue found within the c-Myc SH3-binding motif. Our data provide a structure-based model of the c-Myc/Bin1 interaction and suggest a mode of regulation that may be important for c-Myc function as a regulator of gene transcription.
A structure-based model of the c-Myc/Bin1 protein interaction shows alternative splicing of Bin1 and c-Myc phosphorylation are key binding determinants.,Pineda-Lucena A, Ho CS, Mao DY, Sheng Y, Laister RC, Muhandiram R, Lu Y, Seet BT, Katz S, Szyperski T, Penn LZ, Arrowsmith CH J Mol Biol. 2005 Aug 5;351(1):182-94. PMID:15992821
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.